As a portable device, a mobile terminal is more frequently used than other portable devices and has become the most frequently used portable device of a user and a main carrier for the communication, information management and entertainment of the user. Due to the characteristics of a portable device, the mobile terminal, whose power supply is realized by means of a built-in battery, usually does not use an external power supply to supply power after being charged. Therefore, the continuous using time of the mobile terminal is completely determined by the electricity quantity of the battery in the device. With respect to a portable device, the using time of the battery is an important technical reference index.
Currently, the power supply of the mobile terminal is basically based on the built-in rechargeable battery in the mobile terminal. Even for mobile terminals of the same type, their batteries are used independently. When one mobile terminal runs out of power, it is only possible to take out the battery of another mobile terminal and then replace the battery of the mobile terminal, which runs out of power, with the battery of the another mobile terminal, however, the another mobile terminal can not be used at the same time, causing inconvenience to the users. Therefore, in a working environment without charging fittings and with special requirements, the user desires to use the mobile terminals simultaneously when a mobile terminal runs out of power.